Disc or butterfly type valves are well known in the art. Essentially these valves include a disc which is pivoted to open the valve and to thereby control the flow of, among other things, granular materials such as encountered in, for example, pharmaceutical and food industries. The valves may be used in conjunction with hoppers, transport equipment, process machinery, suction pipes, drums and other container equipment.
The aforenoted uses require that a seal be provided between the valve disc and valve body when the valve is closed. The valves must be easily disassembled for cleaning purposes and various disc positions are required for proper material flow control. Additionally, the valves must be readily adaptable for communication with inlet and/or outlet members for receiving the material and for discharging the material in controlled flow into a drum or container or for communication with, for example, a mounting spacer, whereby the valve is mounted between two material transfer tubes.